Effects of Salinity and Drought Stresses on Seed Germination and Seedling Growth of Desert Wheatgrass Agropyron desertorum

Considering forage grass species, germination is one of the important stagesconcerning the growing stage that is often influenced by environmental stresses,particularly salinity and drought stresses. Thus, this study aims to assess the effects ofsalinity and drought stresses on germination characteristics and seedling growth of desertwheatgrass, Agropyron desertorum (Fisch. ex Link) Schult. in laboratory conditions. Twoseparate experiments were conducted using completely randomized design with fourreplicates. Six salinity treatments (control, 50, 100, 150, 200 and 300 mM NaCl) and sixdrought treatments (control, -0.2, -0.4, -0.6, -0.8 and -1 MPa polyethylene glycol) wereutilized in four replicates. Germination percentage and rate were calculated whilecomputing the germinated seeds every day. Growth parameters (rootlet, shoot and seedlinglength), allometric index and seed vigor have been accordingly given. For eachexperiment, one-way ANOVA was used to determine significant effects of treatments andmean comparison was done by the means of Duncan method using SPSS software. Resultsshowed that salinity and drought stresses had the significant effects on germination andgrowth indices of Agropyron desertorum so that germination rate and percentage, rootlength, shoot length, seedling length and seed vigor indices were decreased by increasingthe concentrations of salinity and drought treatments. Also, seed germination and growthwere observed only until -0.4 MPa drought level so that germination at φs = -0.6 MP wascompletely stopped.